From: "ronkean at juno.com" <ronkean at juno.com>
Date: Tue, 1 Jul 2008 05:52:46 GMT
To: WSFAlist at KeithLynch.net
Cc: WSFAlist at KeithLynch.net
Subject: [WSFA] Re: Tunguska event centennial today
Reply-To: WSFA members <WSFAlist at KeithLynch.net>

-- <lees103 at verizon.net> wrote:
    Ron stated "something more or less like that happens on Earth with a=
 =

frequency of about once per hundred years or so, on average."  Declassif=
ied =

Department of Defense satellite data shows that Earth takes a one megato=
n =

meteor strike in the upper atmosphere on the average of once every eight=
 =

months.  =

*
Yes, I was aware of that when I wrote my reply, and I thought about ment=
ioning it.  The Tunguska event was orders of magnitude larger than one m=
egaton, according to what I have read, which is why it is said to be som=
ething that happens every hundred years or so, on average.  That, and th=
e fact that the Tunguska object apparently exploded at just the right he=
ight to have a large effect over a large area.  If a rocky object of the=
 same mass and velocity had simply slammed into the ground  there, witho=
ut exploding in the atmosphere, it would have been much less dramatic.  =
At the other end of the size scale, hundreds of small objects must be hi=
tting the Earth or its atmosphere every day, most of them too small to b=
e noticed unless they happen to hit where and when someone is watching a=
nd/or nearby.

Ron Kean